The objective of this research is to develop an innovative technique and associated instrumentation for anterior capsulotomy and lens emulsification which allows the majority of ophthalmologists to perform these procedures with greater safety and efficacy. The Phase I study focuses on Er:YAG laser lens emulsification. The four objectives of this study are: to identify the Er:YAG pulse induced acoustic effect in lens emulsification, to establish the optimal laser dosimetry, to evaluate through histological techniques the presence or lack thereof of adverse effects to adjacent structures in the eye, and to design a clinically efficacious flexible delivery system for lens emulsification. This basic research is the foundation for further in vivo testing of the technique and instrumentation during the Phase II study. The results from the in vitro and in vivo studies will allow timely development and optimization of the ophthalmic instrumentation. Premier Laser Systems has already clinically demonstrated the advantages of the Er:YAG laser and flexible fiberoptic delivery in performing a smooth, circular anterior capsulotomy on 10 patients. The subsequent procedure for intraocular lens replacement involves the emulsification and aspiration of the opaque lens. In pursuing laser lens emulsification, our preliminary data are variable but illustrate that the Er:YAG laser has the potential to both ablate and acoustically emulsify all grades of lenses including dense grade three and four lenses, which are not amenable to phacoemulsification.